From patchwork Wed Aug 8 09:23:22 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 1293681 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork2.kernel.org (Postfix) with ESMTP id 2C2A8DF223 for ; Wed, 8 Aug 2012 09:24:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ED742A09A4 for ; Wed, 8 Aug 2012 02:24:50 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (smtp.fireflyinternet.com [109.228.6.236]) by gabe.freedesktop.org (Postfix) with ESMTP id 86E989E97C for ; Wed, 8 Aug 2012 02:24:24 -0700 (PDT) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.73.22; Received: from arrandale.alporthouse.com (unverified [78.156.73.22]) by fireflyinternet.com (Firefly Internet SMTP) with ESMTP id 119813622-1500050 for multiple; Wed, 08 Aug 2012 10:24:18 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 8 Aug 2012 10:23:22 +0100 Message-Id: <1344417802-5822-1-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 1.7.10.4 X-Originating-IP: 78.156.73.22 Subject: [Intel-gfx] [PATCH] drm/i915: Add I915_GEM_PARAM_HAS_SEMAPHORES X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+patchwork-intel-gfx=patchwork.kernel.org@lists.freedesktop.org Userspace tries to estimate the cost of ring switching based on whether the GPU and GEM supports semaphores. (If we have multiple rings and no semaphores, userspace assumes that the cost of switching rings between batches is exorbitant and will endeavour to keep the next batch on the active ring - as a coarse approximation to tracking both destination and source surfaces.) Currently userspace has to guess whether semaphores exist based on the chipset generation and the module parameter, i915.semaphores. This is a crude and inaccurate guess as the defaults internally depend upon other chipset features being enabled or disabled, nor does it extend well into the future. By exporting a HAS_SEMAPHORES parameter, we can easily query the driver and obtain an accurate answer. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_dma.c | 3 +++ include/drm/i915_drm.h | 1 + 2 files changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 9cf7dfe..64fd7be 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1009,6 +1009,9 @@ static int i915_getparam(struct drm_device *dev, void *data, case I915_PARAM_HAS_WAIT_TIMEOUT: value = 1; break; + case I915_PARAM_HAS_SEMAPHORES: + value = i915_semaphore_is_enabled(dev); + break; default: DRM_DEBUG_DRIVER("Unknown parameter %d\n", param->param); diff --git a/include/drm/i915_drm.h b/include/drm/i915_drm.h index 8cc7083..2f0d472 100644 --- a/include/drm/i915_drm.h +++ b/include/drm/i915_drm.h @@ -305,6 +305,7 @@ typedef struct drm_i915_irq_wait { #define I915_PARAM_HAS_LLC 17 #define I915_PARAM_HAS_ALIASING_PPGTT 18 #define I915_PARAM_HAS_WAIT_TIMEOUT 19 +#define I915_PARAM_HAS_SEMAPHORES 20 typedef struct drm_i915_getparam { int param;